A ‘pious pessimism’ pervaded much of archaic Greek poetry: ‘It is for the gods to know and men merely to opine’ was the prevailing sentiment. However, in the late 6th century a set of independent-minded individuals began to move away from the older pessimism to embrace a more optimistic and secular outlook. In various ways they maintained that mere mortals could, if they were prepared to undertake the appropriate inquiries, achieve a clear and sure understanding of the entire cosmos. Heraclitus (...) and Parmenides offered the most detailed lines of investigation, but both Pythagoras and Empedocles presented themselves as savants able and willing to impart their wisdom to all those prepared to listen to and embrace their teachings. Among the most important elements in this transition were the concepts of phusis or the essential nature of a th’ing, and the logos or rational account in which that nature could be formulated. -/- . (shrink)